1. Field of the Invention
The present general inventive concept relates to an image forming apparatus having a removable developer cartridge, and more particularly, to a developer cartridge to supply a developer, and an image forming apparatus having the same.
2. Description of the Related Art
Generally, an electrophotographic image forming apparatuses, such as copier, printer, multi-function unit, or facsimile, includes a photosensitive medium on which an electrostatic latent image is formed, a developing device to developing an electrostatic latent image on the photosensitive medium with a developer, a transfer device to transfer the developed image onto a printing medium, and a fusing device to fix the transferred image into the printing medium.
A color image forming apparatus having a removable developer cartridge generally includes a plurality of color developer cartridges removably mounted on a main body to supply developers of different colors. Accordingly, an expired developer cartridge can be replaced with a new one.
A removable developer cartridge for use in an image forming apparatus generally includes a cartridge frame that includes a developer chamber and a developer discharging port, a developer conveying unit such as an auger which is rotatably mounted on the cartridge frame to agitate developer within the developer chamber and convey the developer towards the developer discharging port.
The image forming apparatus also includes a main body having a driving unit to rotate the auger of the developer cartridge, and a developer conveying duct to connect the developer discharging port of the developer cartridge with the developing cartridge.
As the developer cartridge is mounted on the main body of the image forming apparatus, the auger and the driving unit are connected with each other by a coupling, and as a result, the auger rotates as the image forming apparatus starts an operation. The rotation of the auger agitates the developer within the developer chamber of the developer cartridge, causing the developer to be conveyed towards the developer discharging port. Accordingly, the developer is discharged through the developer discharging port and supplied to the developing cartridge to be used in a developing process.
Because the amount of developer to discharge through the developer discharging port during the auger's conveying of developer is limited, toner sometimes accumulates and hardens particularly in a developer discharging space that can be defined as the vicinity to the developer discharging port, causing the auger to be locked and subsequently interrupting supply of the developer.
Particularly when the developer distribution within the developer cartridge is unbalanced due to an impact exerted during shipping, or when a developer cartridge is exchanged, the delivery pressure reaches a maximum value. Because of the limited absolute quantity of developer to discharge through the developer discharging port, auger is highly likely to be locked, causing interruption of developer supply.
The above problems may be lessened by decreasing the amount of developer being conveyed. However, this would be disadvantageous especially when an image consumes a relatively large amount of a developer, because a system would not be directly printing but wait until the developer is sufficiently supplemented. As a result, the images requiring a large amount of a developer are frequently printed with interruptions.
It has been suggested that an oppositely-spiraling wing be added to an end of the auger to reduce a developer delivery pressure. Although this may be effective in temporarily increasing the developer delivery pressure, the auger can be locked by the hardened developer formed inside a developer cartridge, and ability to supply the developer is also deteriorated than a conventional cartridge.